Recently, optical recording media are attracting attention since a great amount of information can be recorded and are used in various applications. Methods for three dimensionally recording data (hereinafter, referred to as “a multilayer optical recording method, occasionally”) are proposed to further increase the recording density. For example, Y. Kawata et al. reported a technology in which multilayer optical recording is conducted on a photopolymer material comprising a photoreactive component in the photopolymerization (for example, refer to Non-Patent Reference 1). However, heretofore, the multilayer optical recording medium for conducting the multilayer optical recording has a problem in that crosstalk of data takes place during multilayer recording and reading. As the method for preventing the crosstalk, the distance between layers in the optical recording medium may be increased. In this case, it is inevitable that the recording density is decreased, and a problem arises in that the number of the optical recording layer is inevitably limited since light used for reading and writing the record is absorbed in the passage.
To decrease the crosstalk described above, an optical recording medium having two or more recording layers in which a non-recording layer comprising a material not allowing recording of optical informations with the light for recording is disposed partially or entirely between layers of the two or more recording layers described above is proposed (for example, refer to Patent Reference 1). For the formation of the recording layer and the non-recording layer constituting the optical recording medium, in general, each layer is formed in accordance with the spin coating process to laminate the layers. However, the lamination in accordance with the spin coating process has problems in that formation of layers having a great area is difficult, productivity is small, and accuracy of the thickness of each layer and the entire layer is small.
As a means for overcoming the above problems, a process in which a multilayer structural material is obtained by successively laminating a sheet material in which an optical recording layer comprising a photosensitive material and a pressure sensitive adhesive layer are laminated, is proposed (for example, refer to Patent Reference 2). The multilayer optical recording medium having the multilayer structural material described above has excellent accuracy of thickness with respect to each layer and the entire medium, and a medium having a great area can be produced. However, when it is desired that the thickness of the optical recording layer is decreased (to 1,000 nm or smaller) in the process using a sheet utilizing a pressure sensitive adhesive, a problem arises in that strength of the optical recording layer is decreased, and the optical recording medium is occasionally broken when the process film is removed. When the amount of the matrix material (the binder) in the optical recording layer is increased to increase the strength, a problem arise in that recording sensitivity of the optical recording layer is decreased although the removal is made possible.    [Patent Reference 1] Japanese Patent Application Laid-Open No, Heisei 11 (1999)-250496    [Patent Reference 2] Japanese Patent Application Laid-Open No. 2005-209328    [Non-Patent Reference 1] Appl. Opt., 35, 2466 (1966)